The "Companions of Muhammad," known as the Sahabah, were the close followers and supporters of the Prophet Muhammad during his lifetime. They played a crucial role in the early spread of Islam and were instrumental in the establishment of the Muslim community in Medina after the Hijra, or migration, from Mecca. These companions included notable figures such as Abu Bakr, Umar, Uthman, and Ali, who later became the first four caliphs of the Islamic state. Their teachings and actions are highly regarded in Islamic tradition, and they are often cited in Hadith, which are records of the sayings and actions of the Prophet.